Wiper strip for windshield wipers

ABSTRACT

A wiper strip ( 18 ) for windshield wipers includes a profile spine ( 20 ) and a function part ( 22 ) that is connected to the profile spine ( 20 ) via a tilting bridge piece ( 26 ) and that bears against it in the tilted position. The functional part ( 22 ) includes a supporting section ( 30 ) that is connected to the profile spine ( 20 ) via the first tilting bridge piece ( 26 ) and to a wiper wedge ( 32 ) via a second tilting bridge piece ( 28 ).

BACKGROUND OF THE INVENTION

The invention is based on a wiper strip for windshield wipers.

Known windshield wipers comprise a wiper arm constructed out of amounting part and a hinged part with a wiper bar hinge-mounted on themounting part via a hinged joint. A hook-shaped end of the wiper barusually grips in a hinging compartment of a wiper blade that is formedby two lateral supports of a center strap, and encloses a pivot pin. Thejoint designed in this fashion guides the wiper blade over the vehiclewindow during the swivelling movement.

The wiper blade consists of a multisectional carrying strap system withsecondary straps hinge-mounted on the center strap, of which at least afew hold a wiper strip by means of claws on their ends. The long wiperstrip is made of rubber and has a profile having two main sections: aprofile spine, and a functional part. The wiper strip is connected tothe carrying strap system at the profile spine and, in fact, by theclaws of the claw straps gripping in opposing longitudinal grooves ofthe profile spine. In so doing, the claws enclose a part of the profilespine that comprises at least one further longitudinal groove in which aspring is housed. If two springs are used, they lie symmetricallyarranged in opposing longitudinal grooves. Wiper blades are also knownin which a spring is provided in a centrical longitudinal channel of theprofile spine. During operation, the springs should evenly distribute abearing force directed toward the wiper blade across the entire lengthof the wiper strip and stiffen it at the same time.

The profile spine is connected to the functional part of the wiperstrip—which comprises a wiper wedge and a wiper lip—via a thin bridgepiece. The cross-section of the wiper wedge has the shape of a nearlyisosceles triangle, the base side of which points toward the connectingbridge piece, while the wiper lip is integrally moulded on the tip.During wiping, the wiper blade is loaded in the direction toward thevehicle window by means of the bearing force, and the wiper lip bearsagainst the vehicle window. Additionally, a force created by theswivelling movement acts transversely on the rubber profile. While theprofile spine is moved by the side force, the wiper lip remains in itsposition at first. The thin bridge piece between the profile spine andthe functional part thereby acts as a tilting joint due to its highelastic deformability, so that the wiper lip on the functional part moreor less takes on a pitch of 45° in relation to the glass surface. Thisdragged position is the working position of the wiper lip. In thisposition, the wiper wedge is tipped over so far that its outside topshoulder touches the underside of the profile spine.

As a result of the oscillating wiping motion of the windshield wiper,reversal points result in the end positions of the motion. Here, thewiper wedge folds over in the opposite direction and then assumes adragged working position once more. This process of folding overproduces an unpleasant noise in traditional windshield wipers.Additionally, the wiper rubber is elastically deformed to a great extentin the region of the tilting bridge piece. Over the course of service,this leads to a permanent deformation of the wiper rubber profile, whichonly impairs the wiper function of the windshield wiper at first, buteventually even prevents the folding-over action.

A wiper strip is made known in DE 91 04 461.8 U1 in which a dampingstrip is provided between the profile spine and the striking shoulder ofthe wiper wedge. When the functional part of the wiper strip folds overat the reversal point, the shoulder first strikes against the dampingstrip and pushes it until it comes to rest against the profile spine. Asa result, the striking velocity is decelerated, and the noise producedduring the folding-over action is quieted. An acute angle α between thedamping strip and the profile spine, the tip of which points toward thetilting bridge piece, also causes the damping resistance to increase asthe deformation of the damping strip increases. The damping stripprevents the angle of attack of the wiper lip in relation to the vehiclewindow from being reduced, so that the alternate bending load of thetilting bridge piece is unchanged.

SUMMARY OF THE INVENTION

According to the invention, the functional part of a wiper stripincludes a supporting section that is connected to the profile spine viaa first tilting bridge piece and to the wiper wedge via a second tiltingbridge piece. The cross-section of the supporting section has the shapeof an isosceles trapezoid, the base side of which points towards thefirst tilting bridge piece. The supporting section therefore follows abasic shaping of the functional part, which has its greatest width onthe side facing the first tilting bridge piece and decreasescontinuously toward the exposed end of the wiper lip.

During operation, the functional part tilts in a first action to theside until a top shoulder of the supporting section touches theunderside of the profile spine. The wiper lip is now tilted only at afirst partial tilt angle. As the movement progresses, the wiper wedgetilts to the side until its top shoulder touches the underside of thesupporting region. Only now does the wiper lip have a necessary tiltangle of nearly 45° in relation to the vehicle window. According to theinvention, the working position of the wiper lip is reached in twoactions that take place at different times. The advantage of thisprocedure is a dampened folding-over of the functional part of the wiperstrip at the reversal points of the swivelling movement combined with agreatly diminished folding-over noise.

A further advantage of this profile design also lies in the fact that anoptimal relationship exists between geometric folding-over and elasticdeformation, in that the entire tilt angle is distributed over the twotilting bridge pieces and, therefore, the deformation of the functionalsection associated with this is distributed over the two tilting bridgepieces, so that each tilting bridge piece is loaded with only a part ofthe alternate bending load. Localized stress overloads that occur intraditional wiper strips having only one tilting bridge piece do notoccur here. Moreover, undercuts that expand the height of the open spacebetween the lower edge of the profile spine and the base surface of thetrapezoidal supporting section toward the tilting bridge piece reducethe elastic deformability of the first tilting bridge piece. Accordingto the invention, further undercuts are also provided in the open spacesbetween the supporting section and the wiper wedge. The tilting behaviorof the tilting bridge pieces can be coordinated with each other by meansof the shaping of the open spaces and undercuts, and preferably in sucha fashion that the first tilting bridge piece repeatedly participates inthe tilting motion, while the tilting motion of the second tiltingbridge piece largely does not take place until the supporting section isalready resting against the profile spine.

A reduced elastic deformation favorably affects the life of the wiperrubber and prevents a permanent deformation of the wiper profile fromoccurring as a result of high elastic deformation over the course ofservice. The embodiment of the profile spine remains largely unaffectedby the design of the functional section according to the invention, sothat such wiper rubber profiles can be used in wiper blades with themost diverse claw shapes and in “unarticulated” wiper blades.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages arise from the following drawing description.Exemplary embodiments of the invention are presented in the drawing. Thedrawing, the description, and the claims contain numerous features incombination. One skilled in the art will advantageously consider themindividually as well and combine them into reasonable furthercombinations.

FIG. 1 is a side view of a wiper blade with carrying strap system,

FIG. 2 is an enlarged sectional view along the line II—II in FIG. 1,

FIG. 3 is an enlarged view of a wiper rubber profile in partiallyfolded-over position,

FIG. 4 is an enlarged view of a wiper rubber profile in workingposition,

FIG. 5 is an unarticulated wiper blade, and

FIG. 6 is a view along the line VI—VI in FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A wiper blade 10 comprises a center strap 12, on the ends of whichsecondary claw straps 14 with claws 16 for accommodating a wiper strip18 are hinge-mounted (FIG. 1). The wiper strip 18 is long straggling andis enclosed by the claws 16 at an attachment point at a plurality ofpoints.

FIG. 2 shows an enlarged, sectional view through a claw 16. The claw 16encloses the attachment point of the wiper strip 18—a “profile spine”20—that preferably has a total width of 6 to 10 mm and a total height of3.5 to 7 mm. Additionally, the profile spine 20 is strengthened by twosprings 24 as stiffening elements. If only one spring 24 is used, it isusually situated in the center. Depending on the type of vehicle, thethickness of a spring 24 varies between 0.7 and 1.2 mm, and the widthvaries between 2.5 and 4.5 mm.

The profile spine 20 is connected to the second part of the wiper strip18—the functional part 22—via a first tilting bridge piece 26. Accordingto the invention, the functional part 22 is formed out of a supportingsection 30 and a wiper wedge 32 with integral wiper lip 34. Thesupporting section 30 thereby abuts the first tilting bridge piece 26and is connected to the wiper wedge 32 by means of a second tiltingbridge piece 28. The functional part 22 also has its greatest width ofpreferably 4 to 6 mm on the side facing the first tilting bridge piece26, and the width of the supporting section 30 and the wiper wedge 32decreases continuously toward the exposed end of the wiper lip 34.Moreover, the functional part 22 advantageously has a total height of 4to 7 mm.

The profile of the wiper strip 18 without springs 24 is also shownenlarged in FIG. 3. A cover strip 36 limits the opposing longitudinalgrooves 38 for the springs 24 on the one side. On the other side, thelongitudinal grooves 38 are limited by intermediate pieces 40 that alsoform a side wall for two more longitudinal grooves 42 into which theclaws 16 of the claw strips 14 grip. The longitudinal grooves 42 arelimited on the side facing the vehicle window 56 by further cover strips44, the purpose of which is to prevent the claws 16 from damaging thesurface of the vehicle window 56 to be wiped during operation of thewindshield wiper. The dimensions of the previously-described parts ofthe profile spine 20 depend on the vehicle type and the thickness of thesprings 24, so that the cover strip 36 is 0.5 to 2 mm high, theintermediate walls 40 between the longitudinal grooves 38 and 42 have athickness of 0.6 to 1.0 mm, and the cover strips 44 between thelongitudinal grooves 42 and the functional part 22 have a thickness of0.5 to 1.0 mm.

According to the invention, the first tilting bridge piece 26—theconnection between the profile spine 20, and the functional part 22—isformed by two opposing open spaces 46 extending in the longitudinaldirection of the wiper strip 18 and advantageously has a width of 0.5 to1 mm and a height of 0.6 to 1.4 mm. In the drawing, the tilting bridgepiece 26 has an elastic deformation that occurs at the beginning of thefolding-over action at the reversal points of the swivelling movement.The functional part 22 is thereby tilted to one side at a first partialtilt angle φ₁, and a shoulder 50 on the upper edge of the trapezoidalsupporting section 30 that is also located on this side bears againstthe cover strip 44. The dimension of the partial tilt angle φ₁ or thedeformation of the tilting bridge piece 26 is determined by the heightof the open space 46, which amounts to 0.6 to 1.4 mm according to theinvention. So as to elastically deform the first tilting bridge piece 26as little as possible, however, the open spaces 46 expand in the regionof the first tilting bridge piece 26 toward the profile spine 20 bymeans of undercuts 48 that are 0.4 to 0.8 mm high.

The second tilting bridge piece 28 is also formed by two opposing openspaces 52 extending in the longitudinal direction of the wiper strip 18that have a height of 0.3 to 0.8 mm and a distance of 0.8 to 1.5 mm fromthe upper edge of the supporting section 30. The second tilting bridgepiece 28 is located in the middle of the functional part 22 between theopen spaces 52 and has the same height and a width of 0.4 to 1 mm.

In FIG. 4, the functional part 22 is completely folded over andtherefore shown in the end position of the folding-over action. Here, atop shoulder 54 of the wiper wedge 32 bears against a lower edge of thesupporting section 30. A tilt angle φ in relation to the vehicle windowrequired for the working position of the wiper lip 34 is consequentlyformed by a first partial tilt angle φ₁ and a second partial tilt angleφ₂. In order to achieve a smallest-possible elastic deformation of thesecond tilting bridge piece 28 as well, undercuts 58 expand the openspaces 52 in the region of the second tilting bridge piece 28 by 0.2 to0.4 mm in height.

In the embodiment shown in FIG. 5 and FIG. 6, the profile spine 20comprises a cover strip 60 that is secured to an unarticulated carrier62, e.g., by means of cementing, vulcanization, or another suitableprocedure. The carrier 62 is composed of an elastic material, e.g.,metal or a plastic that can also be strengthened using glass fibers orcarbon fibers. It has an articulated axle 64 that is enclosed by ahook-shaped end or an adapter of a wiper bar 66. The carrier 62 iscurved in the longitudinal direction, so that a pressure forcedistributed across the length results when it is pressed against thevehicle window 56.

What is claimed is:
 1. A wiper strip (18) for windshield wipers,comprising: a profile spine (20) and a functional part (22) that isconnected to the profile spine (20) via a tilting bridge piece (26) andthat bears against it in the tilted position, wherein the functionalpart (22) includes a supporting section (30) that is connected to theprofile spine (20) via the first tilting bridge piece (26) and to awiper wedge (32) via a second tilting bridge piece (28), wherein theprofile spine (20) has a total width of 6 to 10 mm and a total height of3.5 to 7 mm, wherein grooves (38) for accommodating springs (24) areprovided on the opposing longitudinal sides, wherein the thickness ofthe springs (24) is between 0.7 and 1.2 mm and the width of each spring(24) is between 2.5 and 4.5 mm, wherein the profile spine (20) islimited at the top by means of a cover strip (38) that is 0.5 to 2 mmhigh, wherein further opposing longitudinal grooves (42) abut thelongitudinal grooves (38) in the direction facing the functional part(22), wherein intermediate walls (40) between the longitudinal grooves(38) and (42) have a thickness of 0.6 to 1 mm, and wherein covers strips(44) between the longitudinal grooves (42) and the functional part (22)have a thickness of 0.5 to 1 mm.
 2. The wiper strip (18) according toclaim 1, wherein the first tilting bridge piece (26) and the secondtilting bridge piece (28) are coordinated with each other in such afashion that, when the functional part (22) tilts, the first tiltingbridge piece (26) folds completely over at first, and the supportingsection (30) bears against the profile spine (20), while the secondtilting bridge piece (28) then folds over and the wiper wedge (32) ofthe functional part (22) bears against the supporting section (30) withone shoulder (50).
 3. A wiper strip (18) for windshield wipers,comprising: a profile spine (20) and a functional part (22) that isconnected to the profile spine (20) via a tilting bridge piece (26) andthat bears against it in the tilted position, wherein the functionalpart (22) includes a supporting section (30) that is connected to theprofile spine (20) via the first tilting bridge piece (26) and to awiper wedge (32) via a second tilting bridge piece (28), wherein thefunctional part (22), including the supporting section (30), has itsgreatest width of preferably 4 to 8 mm on the side facing the firsttilting bridge piece (26), wherein the width of the supporting section(30), a wiper wedge (32), and the wiper lip (34) decreases continuouslytoward the exposed end of the wiper lip (34) to a value of 0.5 to 1 mm.4. The wiper strip (18) according to claim 3, wherein the functionalpart (22), including the supporting section (30), has a total height of4 to 7 mm.
 5. A wiper strip (18) for windshield wipers, comprising: aprofile spine (20) and a functional part (22) that is connected to theprofile spine (20) via a tilting bridge piece (26) and that bearsagainst it in the tilted position, wherein the functional part (22)includes a supporting section (30) that is connected to the profilespine (20) via the first tilting bridge piece (26) and to a wiper wedge(32) via a second tilting bridge piece (28), wherein the second tiltingbridge piece (28) is formed by two opposing open spaces (52) extendingin the longitudinal direction of the wiper strip (18) that are 0.3 to0.8 mm high and are situated 0.8 to 1.5 mm away from the upper edge ofthe supporting section (30), wherein a distance of 0.4 to 1 mm remainsbetween the open spaces (52) in the middle of the functional part (22)for the second tilting bridge piece (28), and wherein the height of thesecond tilting bridge piece (28) corresponds to the height of the openspaces (52).
 6. The wiper strip (18) according to claim 5, wherein theopen spaces (52) expand in the region of the second tilting bridge piece(28) toward the supporting section (30) by means of an undercut (58)that increases the height of the open spaces (52) by 0.2 to 0.4 mm.
 7. Awiper strip (18) for windshield wipers, comprising: a profile spine (20)and a functional part (22) that is connected to the profile spine (20)via a tilting bridge piece (26) and that bears against it in the tiltedposition, wherein the functional part (22) includes a supporting section(30) that is connected to the profile spine (20) via the first tiltingbridge piece (26) and to a wiper wedge (32) via a second tilting bridgepiece (28), wherein the first tilting bridge piece (26) is formed by twoopposing open spaces (46) extending in the longitudinal direction of thewiper strip (18) and has a width of 0.5 to 1 mm and a height of 0.6 to1.4 mm, wherein the open spaces (46) have a height of 0.4 to 0.8 mm andexpand in the region of the first tilting bridge piece (26) toward theprofile spine (20) by means of undercuts (48).
 8. The wiper strip (18)according to claim 7, wherein the profile spine (20) is secured to anunarticulated carrier (62) by means of a cover strip (60).